Previous studies on the impact of technology on performance (usefulness) have looked at the Information System (IS) in its role as supplier of information (informating role) and thus they have studied the influence of information quality and system quality on usefulness. However, an IS also has a role in the automation of tasks (automating role), which these studies do not take into account. Accordingly, this paper proposes a factor model that (1) includes explicitly both roles; (2) considers that informating and automating roles mediate the relation between these technological factors (information quality and system quality) and usefulness and (3) includes a system’s level of intervention (i.e. the degree to which technology participates in carrying out the tasks) as an additional factor that determines usefulness. Using a questionnaire, data were gathered on 229 Enterprise Resource Planning system users from different organisations and functional areas and structural equations model was used for analysis. Results show that information quality explains usefulness through both roles. System’s level of intervention explains usefulness through the automating role and system quality explains usefulness through the informating role. The factors’ differentiated effects through each role may help managers to establish more effective criteria and priorities in the various stages of an IS’s life cycle.